| Objective To investigate the change and prognostic value of heart rate turbulence (HRT) in patients with acute myocardial infarction (AMI).Methods Ninety-seven patients with AMI for 1-3 weeks (AMI group) and 65 healthy controls (control group) were chosen. Detailed clinical data of these subjects were collected, including Ultrasonic Cardiogram (UCG) and 24-hour ambulatory electrocardiograph (Holter) and so on, to obtain left ventricular ejection fraction (LVEF), heart rate variability (HRV), mean heart rate and heart rate turbulence including turbulence timing (TT), turbulence onset (TO) and turbulence slope (TS). Patients with AMI were divided into high-risk group (Killip II -IV) and low-risk group (Killip I) according to Killip classification, and high-risk group and low-risk group according to whether complicating malignant ventricular arrhythmia. The value of above indexes were compared between AMI group and control group, and between high-risk group and low-risk group of AMI. Then patients were followed up. The primary end point was occurring heart incident (including myocardial infarction, angina pectoris, malignant arrhythmia and sudden cardiac death), and patients with AMI were divided into event group and non-event group according to the outcome of following-up. High-risk factors in prognosis were determined according to previous danger stratification and were analyzed through logistic regression analysis to assess the predictive value of HRT and other traditional indexes for high-risk patients with subsequent heart incident after AMI.Results 1. The values of TT and TO of the patients with AMI were significantly higher than those of the control group, and the values of TS were lower than those of the control group (P< 0.05). 2. Patients in Killip class II -IV had significantly lower TS values than those in class I (P <0.05), and patients with malignant ventricular arrhythmia had significantly greater TT and lower TS values than those who were without malignant ventricular arrhythmia(P<0.05). 3. Ninety-three patients with AMI were followed up and during a follow-up of (19.20+11.97) months, 20 patients suffered heart incident again. Patients in event group had significantly greater TT and TO and lower TS values than those in non-event group(P<0.05), and the phenomenon of HRT in event group attenuated significantly. 4. Both TO and TS were significantly correlated with age and mean heart rate, but were not corrected with SDNN and LVEF, and TT was not corrected with other risk predictors. 5. In univariate analysis, age, history of previous myocardial infarction, LVEF, TS, TT, combination of TO and TS and combination of TT, TO and TS were related with the happenings of heart incident. In multivariate analysis, only the combination of TT, TO and TS, combination of TO and TS, TS, LVEF, history of previous myocardial infarction were related with heart incident. Both in univariate and multivariate analysis, the combination of TT, TO and TS was the strongest risk predictor (OR=8.632; OR= 6.133,P<0.01).Conclusions The difference of HRT between AMI group and control group or between high-risk group and low-risk group of patients with AMI is significant, especially in TT and TS. TT was not influenced by age and mean heart rate when it was measured, and TT was dichotomized at the median 9 and compared to conventional risk predictors in logistic regression analysis. The result of analysis was TT was associated with the development of clinical end points, and the combination of abnormal TT, TO and TS was the most powerful multivariate risk predictor for the subsequent heart incident. HRT could serve as a strong predictor for the subsequent development of poor outcomes in AMI patients.
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